From the oops-maybe-we-shouldn't-have-shut-down-SP2Torrent.com dep't, the Washington Post is carrying a story (Windows Upgrade Causing Campus Headaches) about numerous universities actively blocking SP2 updates because, among other things, they take up too much bandwidth to download directly from the Microsoft site:

Worried that the upgrade could conflict with other applications running on university networks, and a related concern that thousands of students attempting to download the software could bring campus computer networks to a standstill, technology administrators at some universities have taken steps to block an automatic service that downloads the software.

...

"Our primary concern is the impact this will have on our network and the length of time it would take to get from Microsoft directly," said Damon Palyka, a computer security technician at the school.